ww/test/wcc/818_arr_ptr_global.c

/*
 * 818_arr_ptr_global — `.ptr` on a fixed-size array is the sanctioned ww
 * spelling for &A[0] (task #13 divergence-record, drew ruling
 * .ai/drew-gapa-ptr-ruling.md). For a LOCAL array the backing pointer is the
 * frame slot (LEAQ off(BP)); for a module GLOBAL array (let or def) it is the
 * symbol address (LEAQ name(SB)). cstage cgen emitted LEAQ off(BP) for BOTH
 * flavours — and for a global, off==0, so `*A.ptr` read the frame's first
 * slot = stack garbage (the GAP-A.ptr silent miscompile, task #11; the
 * off==0/global base-selection class of #231/#48).
 *
 * The fix (cmd/w6c/cgen.c N_DOT array .ptr arm + selfhost cgenexpr.ww def
 * arm): when off==0 and the operand is a module global (let_islet ||
 * def_isarraydef), emit LEAQ name(SB) instead of LEAQ (BP), mirroring the
 * def-array index base at cgen.c:4367. wwstage's LET-global `.ptr` was
 * already correct (LEAQ name(SB)); only the DEF-global arm was missing.
 * After this commit local / let-global / def-global `.ptr` are byte-
 * IDENTICAL across both stages.
 *
 *   row              | shape                                   | want
 *   -----------------+-----------------------------------------+------
 *   def_glob_ptr     | def A:[3]int, *A.ptr   (THE regression) | 10
 *   let_glob_ptr     | let G:[3]int, *G.ptr   (BP→SB converge) | 5
 *   local_ptr        | local [3]int, (a.ptr)[2] (unchanged)    | 3
 *
 * def_glob_ptr / let_glob_ptr are the mutation-sane rows: pre-fix they read
 * stack garbage. local_ptr guards the 14 live local-`.ptr` consumers (cgen
 * unchanged for locals). A byte-id row pins cstage==wwstage `.s` for the
 * def-global `.ptr` source (the convergence the fix delivers).
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>

static int
runwait(const char *cmd)
{
	int rc = system(cmd);
	if (rc == -1) return -1;
	if (WIFEXITED(rc)) return WEXITSTATUS(rc);
	return -1;
}

struct row { const char *label; const char *src; int want; };

static const struct row rows[] = {
	/* def_glob_ptr — THE regression pin: pre-fix `*A.ptr` reads stack
	 * garbage because cstage LEAQ (BP)'d the def-global base. */
	{ "def_glob_ptr",
	  "package main;\n"
	  "def A: [3]int = [10, 20, 30];\n"
	  "export fn main() i32 = {\n"
	  "\tlet p: *int = A.ptr;\n"
	  "\treturn (*p): i32;\n"
	  "};\n",
	  10 },

	/* let_glob_ptr — pins the cstage BP→SB convergence (wwstage was
	 * already right for let-global, so this closes the latent cs≠ww). */
	{ "let_glob_ptr",
	  "package main;\n"
	  "let G: [3]int = [5, 6, 7];\n"
	  "export fn main() i32 = {\n"
	  "\tlet p: *int = G.ptr;\n"
	  "\treturn (*p): i32;\n"
	  "};\n",
	  5 },

	/* local_ptr — the 14-site regression guard; cgen unchanged for a
	 * LOCAL array (off!=0 → LEAQ off(BP)). p[2] strides element 2. */
	{ "local_ptr",
	  "package main;\n"
	  "export fn main() i32 = {\n"
	  "\tlet a: [3]int = [1, 2, 3];\n"
	  "\tlet p: *int = a.ptr;\n"
	  "\treturn p[2]: i32;\n"
	  "};\n",
	  3 },
};

static int
run_driver(const char *driver, const struct row *r, int i)
{
	char tmpdir[64], src[128], outbin[128], rmcmd[160], cmd[1024];
	snprintf(tmpdir, sizeof tmpdir, "/tmp/apg_%d_d_%d", getpid(), i);
	mkdir(tmpdir, 0755);
	snprintf(src,    sizeof src,    "%s/apg_%d_%d.ww", tmpdir, getpid(), i);
	snprintf(outbin, sizeof outbin, "%s/apg_%d_%d",    tmpdir, getpid(), i);
	snprintf(rmcmd,  sizeof rmcmd,  "rm -rf %s", tmpdir);

	FILE *f = fopen(src, "wb");
	if (!f) { runwait(rmcmd); return -1; }
	fputs(r->src, f);
	fclose(f);

	snprintf(cmd, sizeof cmd, "%s build -o %s %s 2>/dev/null",
	    driver, outbin, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: build via %s failed\n",
		    r->label, driver);
		runwait(rmcmd);
		return -1;
	}

	int got = runwait(outbin);

	runwait(rmcmd);
	return got;
}

/* asm_byte_identical — w6c vs w6c_ww .s for the same source must match. */
static int
asm_byte_identical(const char *bin, const struct row *r, int i)
{
	char src[64], cs[64], ws[64], cmd[1024];
	snprintf(src, sizeof src, "/tmp/apg_asm_%d_%d.ww", getpid(), i);
	snprintf(cs,  sizeof cs,  "/tmp/apg_asm_%d_%d_c.s", getpid(), i);
	snprintf(ws,  sizeof ws,  "/tmp/apg_asm_%d_%d_w.s", getpid(), i);

	FILE *f = fopen(src, "wb");
	if (!f) return -1;
	fputs(r->src, f);
	fclose(f);

	snprintf(cmd, sizeof cmd, "%s/w6c -o %s %s 2>/dev/null", bin, cs, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c errored\n", r->label);
		unlink(src);
		return -1;
	}
	snprintf(cmd, sizeof cmd, "%s/w6c_ww -o %s %s 2>/dev/null",
	    bin, ws, src);
	if (runwait(cmd) != 0) {
		fprintf(stderr, "row[%s]: w6c_ww errored\n", r->label);
		unlink(src); unlink(cs);
		return -1;
	}

	FILE *fc = fopen(cs, "rb");
	FILE *fw = fopen(ws, "rb");
	int rc = 0;
	if (!fc || !fw) {
		rc = -1;
	} else {
		for (;;) {
			int a = fgetc(fc);
			int b = fgetc(fw);
			if (a != b) { rc = -1; break; }
			if (a == EOF) break;
		}
	}
	if (fc) fclose(fc);
	if (fw) fclose(fw);
	if (rc != 0)
		fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n",
		    r->label);
	unlink(src); unlink(cs); unlink(ws);
	return rc;
}

int
main(void)
{
	const char *bin = getenv("BIN");
	if (!bin) bin = "out/bin";
	char absbin[1024];
	if (bin[0] != '/') {
		char cwd[1024];
		if (getcwd(cwd, sizeof cwd) == NULL) return 1;
		snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
		bin = absbin;
	}

	char cdrv[1024];
	snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
	char wdrv[1024];
	snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);

	struct { const char *name; const char *path; int gated_on_existence; }
	drivers[] = {
		{ "cstage",  cdrv, 0 },
		{ "wwstage", wdrv, 1 },
		{ NULL, NULL, 0 },
	};

	int n = (int)(sizeof rows / sizeof rows[0]);
	int total = 0, fail = 0;

	for (int d = 0; drivers[d].name; d++) {
		if (drivers[d].gated_on_existence
		    && access(drivers[d].path, X_OK) != 0) {
			fprintf(stderr, "arr_ptr_global: skip %s (no %s)\n",
			    drivers[d].name, drivers[d].path);
			continue;
		}
		for (int i = 0; i < n; i++) {
			int got = run_driver(drivers[d].path, &rows[i], i);
			total++;
			if (got != rows[i].want) {
				fprintf(stderr,
				    "arr_ptr_global[%s][%s]: exit=%d want=%d\n",
				    drivers[d].name, rows[i].label,
				    got, rows[i].want);
				fail++;
			}
		}
	}

	if (access(wdrv, X_OK) == 0) {
		for (int i = 0; i < n; i++) {
			total++;
			if (asm_byte_identical(bin, &rows[i], i) != 0)
				fail++;
		}
	}

	if (fail) {
		fprintf(stderr,
		    "arr_ptr_global: %d/%d fixtures failed\n", fail, total);
		return 1;
	}
	printf("arr_ptr_global: %d/%d ok\n", total, total);
	return 0;
}